FIGURE 7.

A, impairment of mitochondrial DNA following MIOX overexpression under HG ambience. Under LG ambience, two bands corresponding to high molecular weight DNA (∼7.8 kb) (HM) and low molecular weight DNA (∼0.4 kb) (LM) were seen by PCR analyses (lane 1). A mild increase in the intensity of the high molecular weight band is observed following transfection of EV (lane 2). Treatment with HG in the presence or absence of EV showed a notable decrease in the intensity of the HM weight DNA (lanes 3 and 4 versus lanes 1 and 2). MIOX-pcDNA transfection caused a significant decrease in the intensity of the HM band (lane 5 versus lanes 1 and 2). Treatment of such transfected cells with HG ambience resulted in a marked decrease in the intensity of the HM band (lane 6 (asterisk) versus lanes 1 and 2), whereas treatment with MIOX siRNA restored the intensity of the HM band (lane 7 versus lane 6), suggesting that MIOX overexpression in the presence of HG readily damages high molecular weight DNA. B, induction of apoptosis in LLC-PK1 cells following MIOX overexpression under HG ambience. Under basal conditions of LG, no significant apoptosis was observed (B (a)). An HG ambience induced apoptosis in about 5% of cells (B (b), arrows). Upon MIOX-pcDNA transfection, apoptosis increased 2–3-fold (B (c), multiple arrows). Treatment with MIOX siRNA remarkably reduced apoptosis, and a few tiny nuclear fragments were seen (B (d), arrowheads).